JPH09311024A - Shape measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure a shape by eliminating an Abbe error by a constitution wherein a reference mirror and a laser interferometer are provided so that a center axis of a length-measuring passage passes through a measuring point of an object to be measured and is in conformity with a straight line which is in parallel to an axis direction. SOLUTION: A laser interferometer 23, an emission section 33a of an optical cable 33 and a receiver 25 are provided on an upper face of a plane member 12a of a Y stage 12 so that a center axis of a length-measuring passage formed between the laser interferometer 23 for measuring an X coordinate and a reference plane mirror 31 passes through a measuring point P of a displacement meter 1 and is in parallel to an X axis direction of the XY stage 10. A laser interferometer 24, an emission section 34a of an optical fiber cable 34 and a receiver 26 are provided on the upper face of the Y stage 12 so that a center axis of a length-measuring passage formed between the laser interferometer 24 for measuring a Y coordinate and a reference plane mirror 32 passes through the measuring point P of the displacement meter 1 and is in parallel to a Y axis direction of the XY stage 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus for measuring the surface shape of an object, and more particularly to a shape measuring apparatus equipped with a laser interferometer to measure the surface shape of an object with high accuracy.

[0002]

2. Description of the Related Art Conventionally, as a shape measuring apparatus for measuring the surface shape of an object, for example, two axes or three axes that are substantially orthogonal to each other
A displacement meter that detects the measurement point on the surface of the object to be measured is provided on a movable table that moves independently in the axial direction, and this displacement meter keeps the detection signal at the measurement point substantially constant while measuring the surface of the object to be measured. There is known a shape measuring device that moves a moving table so as to move the moving table and measures the surface shape of the object to be measured based on the movement trajectory of the moving table.

An example of this type of shape measuring apparatus is shown in FIG. In FIG. 7, 1 is an optical displacement meter, 10 is an XY stage 10 composed of an X stage 11 and a Y stage 12, and the displacement meter 1 is fixed to the upper surface of the Y stage 12. Further, the DUT 2 is XY
It is fixed to the object set table 3 outside the stage 10. 13 is an actuator that moves the X stage 11 in the X axis direction, 14 is an actuator that moves the Y stage 12 in the Y axis direction, and 15 and 16 are controller drivers that drive the actuators 13 and 14, respectively.

A linear encoder 17 including a main scale 17a attached to the side surface of the X stage 11 and an index scale 17b attached to the apparatus main body is provided on one side surface side of the X stage 11 parallel to the X axis direction. , The amount of movement of the XY stage 10 in the X-axis direction is detected. Further, on one side surface side of the Y stage 12 parallel to the Y axis direction, a linear encoder 18 including a main scale 18a attached to the side surface of the Y stage 12 and an index scale 18b integrally attached to the X stage 11. Is provided, and the Y of the XY stage 10
The amount of movement in the axial direction is detected.

Reference numeral 19 outputs a signal for moving the XY stage 10 to the controller drivers 15 and 16 based on the detection signal output from the displacement meter 1 and the amount of movement of the XY stage 10 detected by the linear encoders 17 and 18. Is input and the movement trajectory of the XY stage 10 is analyzed based on the obtained movement amount to specify the surface shape of the DUT 2, and is configured by, for example, a personal computer.

In this shape measuring apparatus, the XY stage 10 is moved so that the displacement meter 1 moves the measuring point along the surface of the object 2 to be measured, and the moving amount of the XY stage 10 is adjusted by the linear encoders 17 and 18. By detecting, the shape of the measured object in a plane parallel to the XY plane passing through the X axis and the Y axis of the measured object 2 is indirectly measured.

The operation will be described in detail with reference to FIG.
As shown in FIG. 1, first, the DUT 2 is set on the setting table 3, and the XY stage 10 is moved in the X direction so as to move the displacement meter 1 on the Y axis passing through the measurement start point P0 of the DUT 2. It Then, as shown in FIG. 8B, X is set so that the measurement start point P0 of the DUT 2 is within the measurable range of the displacement meter 1.
The Y stage 10 is moved in the Y axis direction. Then, FIG.
As shown in (c), the object to be measured 2 and the displacement meter 1 are kept at a constant distance (to be in the measurable range of the displacement meter 1).
The X stage 11 is moved upward in the figure (X axis direction), and the Y stage 12 is moved left and right in the figure (Y axis direction).
The movement amounts S1 and S2 of the Y stage 10 are detected.
Then, the movement trajectory of the XY stage 10 is analyzed based on the movement amount obtained by the personal computer 19, and the surface shape of the DUT 2 is specified.

However, in the conventional shape measuring apparatus shown in FIG. 7, the linear encoders 17 and 18 are used to detect the moving amount of the XY stage 10, and the linear encoders 17 and 18 are used as a drive unit such as a guide of the XY stage 10. Altitude straightness (linearity)
Was required. This is because the mechanical error caused by the movement of the XY stage 10 becomes the error of the DUT 2.

For example, if the center axis of the guide of the X stage 11 is displaced from the measurement start point P by a displacement + δ in the Y axis direction, the Y stage is arranged so that the object to be measured 2 and the displacement meter 1 are kept at a constant distance. 12 is moved by −δ in the Y-axis direction,
This movement amount −δ is measured as the surface shape of the DUT 2. Therefore, straightness (linearity) is required for the members such as the XY stage 10 and the guides thereof, for example, static pressure air guide is required, and there is a problem that the measuring device becomes expensive.

Therefore, as a means for detecting the amount of movement of the XY stage, a shape measuring device using a laser interferometer is known. An example of this type of shape measuring device is shown in FIG. The same components as those shown in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted.
Further, in the same figure, a personal computer, two controller drivers and the like are omitted.

In FIG. 9, reference numeral 20 is a reference mirror for measuring the X coordinate and the Y coordinate, and the reflecting surface 20a and the reflecting surface 20b are formed so as to form a right angle with each other with high precision, and each of them is in the X axis direction of the XY stage 10. And on the XY stage 10 so as to be orthogonal to the Y-axis direction.
Reference numeral 21 denotes a frequency-stabilized laser light source, and the laser light emitted from this light source 21 is divided into two directions by a prism 22, and is respectively divided into a laser interferometer 23 for X coordinate measurement and a laser interferometer 24 for Y coordinate measurement. Is ejected. The laser light incident on the laser interferometer 23 makes two round trips with the reflecting surface 20a of the reference mirror 20 and is received by the receiver 25, and the laser light incident on the laser interferometer 24 is reflected on the reflecting surface 20b of the reference mirror 20. 2 round trips to and from the receiver 26
Received. The interference signals received by the receivers 25 and 26 are input to a personal computer (not shown), and the movement trajectory of the XY stage 10 is analyzed based on these interference signals to identify the surface shape of the DUT 2.

In this shape measuring apparatus, the XY stage 10
Laser interferometers 23 and 24 and XY arranged outside the
X by the fixed reference mirror 20 on the stage 10.
Since the amount of movement of the Y stage 10 in the X axis direction and the Y axis direction is measured, as in the case of using a linear encoder,
It is possible to eliminate the influence of the straightness error due to the movement of the XY stage 10.

For example, if the center axis of the guide of the X stage 11 is displaced from the measurement starting point P by the displacement + δ in the Y axis direction, the Y stage is arranged so that the object to be measured 2 and the displacement meter 1 are kept at a constant distance. This is because 12 is moved by −δ in the Y-axis direction, but the position of the reflecting surface 20b of the reference mirror 20 seen from the laser interferometer 24 does not change. Further, as this type of shape measuring device, an ultra-high precision three-dimensional measuring machine described in JP-A-4-29206 is reported. In this measuring machine, an XY table 2 is provided on a surface plate 1, a pedestal 3 is provided on the XY table 2, a Z-axis moving table 5 and a laser interference length measuring device are provided on the pedestal 3. Upper support 8
A horizontal mirror is provided as an XY axis reference plane 9 above the Z axis moving base via this support 8. And
A distance Z1 between the surface to be measured of the object 7 to be measured fixed to the surface plate 1 and a specific point on the Z-axis moving table located above the surface, and
Influence of insufficient straightness in the Z-axis direction by measuring the distance Z2 between the XY-axis reference plane 9 and a specific point on the Z-axis moving table 5 located below the reference plane 9 to obtain the shape of the DUT 7. It is possible to measure a large object under measurement while eliminating.

[0014]

However, in the conventional shape measuring apparatus shown in FIG. 9, the so-called Abbe error caused by yawing, pitching, etc., which occurs when the XY stage is moved, is excluded from the measurement. However, in order to minimize the effect of this Abbe error, X
The members such as the Y stage and its guide are required to have straightness (linearity), for example, static pressure air guide is required, and there is a problem that the measuring device becomes expensive.

Further, even in the ultra-high precision three-dimensional measuring machine disclosed in Japanese Patent Laid-Open No. 4-29206, since the laser interferometer length measuring device main body is provided on the frame 3, the optical system becomes complicated. There was such a problem. Therefore, in the present invention, the central axis of the length-measuring path between the laser interferometer and the reference mirror corresponding to each axial direction passes through the measurement points of the object to be measured,
By arranging the reference mirror and laser interferometer so that they match on a straight line parallel to each axial direction, Abbe error can be eliminated and highly accurate shape measurement can be performed at low cost. The purpose is to provide a device.

[0016]

In order to achieve the above object, the invention according to claim 1 is one of a displacement meter for detecting a measurement point on the surface of the object to be measured, and a displacement meter and the object to be measured. One of which is fixed, and a displacement table which independently moves in at least two axial directions of X-axis, Y-axis and Z-axis which are substantially orthogonal to each other and which includes an axis parallel to the detection direction of the displacement meter, Moving means for independently moving the moving table in each axial direction so as to move the measuring point along the surface of the measured object while keeping the detection signal of the measuring point substantially constant, and for each axial direction of the moving table. A laser which is provided so as to correspond to at least an axial direction parallel to the detection direction of the displacement meter, and which forms a length measurement optical path between a reference mirror including a reflection surface serving as a length measurement reference and the reflection surface of the reference mirror. An interferometer and a laser that supplies laser light to the laser interferometer. At least it has a seat supply system 1
A laser interferometer, and a shape measuring device for measuring a surface shape of an object to be measured based on a measurement result of the laser interferometer, wherein the center of the optical path of the laser interferometer is measured. The reference mirror and the laser interferometer are arranged such that the axis passes through the measurement point of the object to be measured and is aligned on a straight line parallel to the axial direction of the movable table.

According to the first aspect of the invention, the center of each length-measuring optical path formed between the laser interferometer and the reference mirror of the laser interferometer, which corresponds to at least the axial direction parallel to the detection direction of the displacement meter. The reference mirror and the laser interferometer are arranged so that the axis passes through the measurement point of the object to be measured and is aligned with a straight line parallel to the axial direction of the movable table. Therefore, it is possible to measure the amount of movement of the displacement table moving table in at least the axial direction corresponding to the detection direction of the displacement gauge while eliminating the Abbe error with the laser interferometer, and thus to improve the shape of the object to be measured. It can be measured with accuracy. Further, since it is not necessary to make the members such as the XY stage or the XYZ stage and the guide highly accurate, the cost of the measuring device can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the laser interferometers are provided so as to measure the respective movement amounts of the movable table in the respective axial directions. The central axis of the measuring optical path of the interferometer is
Each of the reference mirrors and the laser interferometers are arranged so as to coincide with a straight line parallel to the axial direction of the movable table and passing through the measurement points of the object to be measured.

According to a second aspect of the present invention, a plurality of the laser interferometers are provided so as to measure the amount of movement of each of the movable bases in the respective axial directions, and the length measurement optical paths of the plurality of laser interferometers are measured. The reference mirrors and the laser interferometers are arranged such that the central axes of the two pass through the measurement points of the object to be measured and are aligned on a straight line parallel to the axial direction of the movable table. Therefore, it is possible to measure the amount of movement of the displacement table in the axial direction corresponding to at least the detection direction of the displacement meter while eliminating the Abbe error by the laser interferometer measuring device corresponding to all the axial directions of the displacement table. Therefore, it is possible to reliably perform highly accurate shape measurement.

The invention according to claim 3 is the invention according to claim 1 or 2
In the invention described above, the laser supply system has an optical fiber that guides laser light emitted from a laser light source to the laser interferometer. In the invention according to claim 3, since the laser light emitted from the laser light source is guided by the optical fiber to the laser interferometer corresponding to the axial direction of the moving table, the laser light source generator or the like is moved from the moving table or its periphery. It can be installed at a remote location. Further, the emitting part of the optical fiber can be installed on the movable table. Therefore, the degree of freedom in the layout of the laser supply system can be improved, and the device can be made compact. This is because a laser light source generator using a general gas laser is unsuitable for installation on a moving table due to its size and weight.

The invention according to claim 4 is the invention according to claim 1 or 2.
In the invention described above, the laser supply system comprises a semiconductor laser. In the invention according to claim 4, since the laser supply system comprises a semiconductor laser,
Compared with the case of using a gas laser typified by He-Ne laser, the entire device can be remarkably downsized. Further, since the semiconductor laser can be installed on the moving table, the degree of freedom in the layout of the laser supply system can be improved. This is because, in general, a laser light source generator using a gas laser is unsuitable for installation on a moving table due to its size and weight.

According to a fifth aspect of the invention, in the invention according to any one of the first to fourth aspects, the object to be measured and the reference mirror are fixed to the movable table, the displacement meter, the laser interferometer, and the The laser supply system is fixed to the outside of the movable table. In the invention according to claim 5, the object to be measured and the reference mirror are fixed to the movable table, and the displacement meter, the laser interferometer, and the laser supply system are fixed to the outside of the movable table. Therefore, for example, the wiring of the receiver or the like can be installed outside the moving table, so that the wiring does not become an obstacle when the moving table is moved, and the device configuration is simplified.

The invention according to claim 6 is the invention according to claim 3 or 4.
In the invention described above, the displacement meter, the laser interferometer,
In addition, the emitting portion of the optical fiber or the semiconductor laser is fixed on the movable table, and the DUT and the reference mirror are fixed to the outside of the movable table. In the invention according to claim 6, the displacement meter, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the movable table, and the object to be measured and the reference mirror are arranged on the movable table. It is fixed to the outside.
Therefore, the displacement meter, the laser interferometer, and the emission part of the optical fiber or the semiconductor laser have a light weight and a constant weight, so that the moving load of the movable table is reduced and the actuator is designed to realize a suitable followability. Will be easier. This is particularly effective when the weight of the object to be measured and the reference mirror is larger than the weights of the displacement meter and the laser interferometer.

The invention according to claim 7 is the invention according to claim 1 or 2.
In the invention described above, a first moving table that moves independently in each of the axial directions, and one of the displacement gauge and the object to be measured mounted on the first moving table are fixed, A second moving table that independently moves in at least an axial direction parallel to the detection direction of the displacement meter in the axial direction, and the moving means is configured to move the second moving table first with respect to the axial direction in which the second moving table can move. The movable table is moved so as to follow the fluctuation of the low frequency band of the detection signal of the displacement meter, and the second movable table is moved so as to follow the fluctuation of the high frequency band of the detection signal of the displacement meter. It is characterized by

According to a seventh aspect of the invention, the movable table is
A first moving table that moves independently in each of the axial directions;
The displacement table and the object to be measured are mounted on the first moving table, and one of them is moved independently of at least the axial direction parallel to the detection direction of the displacement meter. A second moving table, and the moving means moves the first moving table so as to follow the fluctuation in the low frequency band of the detection signal of the displacement gauge in the axial direction in which the second moving table can move. Then, the second moving table is moved so as to follow the fluctuation of the detection signal of the displacement meter in the high frequency band. For this reason, the moving means moves the first moving table in a low frequency band, that is, the measurement point moves so as to substantially follow the shape of the object to be measured, and the second moving table moves in a high frequency band, that is, the first moving table. It is possible to move the measuring point by moving the moving table so as to follow the vibration of the moving table and the surface roughness of the object to be measured and sharing the control band. Therefore, the measurement can be speeded up.

The invention described in claim 8 is characterized in that, in the invention described in claim 7, the laser supply system has an optical fiber for guiding a laser beam emitted from a laser light source to the laser interferometer. To do. In the invention according to claim 8, since the laser light emitted from the laser light source is guided by the optical fiber to the laser interferometer corresponding to each axial direction of the moving table, the laser light source generator or the like is moved to the moving table or the moving table. It can be installed at any position away from the surroundings. Further, the emitting part of the optical fiber can be installed on the movable table. Therefore, the degree of freedom in the layout of the laser supply system can be improved, and the device can be made compact. This is because a laser light source generator using a general gas laser is unsuitable for installation on a moving table due to its size and weight.

According to a ninth aspect of the invention, in the seventh aspect of the invention, the laser supply system comprises a plurality of semiconductor lasers. According to the invention of claim 9,
Since the laser supply system is composed of a plurality of semiconductor lasers, the entire apparatus can be significantly downsized as compared with the case of using a gas laser represented by a He-Ne laser. Further, since the semiconductor laser can be installed on the moving table, the degree of freedom in the layout of the laser supply system can be improved. This is because, in general, a laser light source generator using a gas laser is unsuitable for installation on a moving table due to its size and weight.

According to a tenth aspect of the invention, in the invention according to any one of the seventh to ninth aspects, the object to be measured and the reference mirror are fixed to the second movable table, and the displacement meter and the laser interferometer are provided. And the laser supply system is fixed to the outside of the movable table. In the invention according to claim 10, the object to be measured and the reference mirror are fixed to the second movable table, and the displacement gauge, the laser interferometer, and the laser supply system are fixed to the outside of the movable table. For this reason, for example, the output of the receiver and the wiring for obtaining can be arranged outside the moving table, so that the wiring does not obstruct the movement of the moving table and the device configuration is simplified.

According to an eleventh aspect of the present invention, in the eighth or ninth aspect of the invention, the displacement meter, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the second movable table. The object to be measured and the reference mirror are fixed to the outside of the movable table. In the invention according to claim 11, the displacement meter, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the second movable table, and the measured object and the reference mirror are moved. It is fixed to the outside of the stand. Therefore, displacement meters, laser interferometers,
In addition, since the weight of the emitting portion of the optical fiber or the semiconductor laser is light and constant, it is easy to design the actuator that reduces the moving load of the first and second moving bases and realizes the suitable followability of the moving bases. Becomes This is particularly effective when the weight of the object to be measured is larger than the weights of the displacement meter and the laser interferometer.

According to a twelfth aspect of the invention, in the invention according to the eighth or ninth aspect, the displacement meter and the second
The laser interferometer and the emitting part of the optical fiber or the semiconductor laser corresponding to the movable axial direction of the movable table are fixed to the second movable table, and the axial direction other than the movable axial direction of the second movable table. Wherein the laser interferometer and the emission part of the optical fiber or the semiconductor laser corresponding to are fixed to the first moving table, and the DUT and the reference mirror are fixed to the outside of the moving table. To do.

According to a twelfth aspect of the invention, the displacement gauge,
In addition, the laser interferometer and the emitting portion of the optical fiber or the semiconductor laser corresponding to the movable axial direction of the second moving table are fixed to the second moving table,
The laser interferometer and the emitting portion of the optical fiber or the semiconductor laser corresponding to an axial direction other than the movable axial direction of the movable table are fixed to the first movable table, and the DUT and the reference mirror are moved. It is fixed to the outside of the stand. Ideally, all the laser interferometers corresponding to each axial direction should be fixed to the second moving table, but the moving load of the second moving table becomes large, and suitable followability of the second moving table is obtained. It may not be possible. Therefore, by reducing the number of laser interferometers fixed to the second moving table and reducing the moving load of the second moving table, the movement of the second moving table can be accelerated. At this time, even if the remaining laser light source and the laser interferometer are on the first movable table, sufficient followability can be obtained without causing an Abbe error.

The invention according to claim 13 is the invention according to claims 1 to 12.
In the invention described in any one of the above, the measured values in the respective axial directions measured by the laser interferometer are ideal based on the error of the squareness between the reference mirrors corresponding to the respective axial directions which is obtained in advance. It is characterized in that it has a conversion means for converting the coordinate values of the orthogonal coordinates. In the invention according to claim 13, the perpendicularity between the plane mirrors corresponding to the respective axial directions is obtained in advance, and the measured values in the respective axial directions measured by the laser interferometer by the converting means are ideal. It is converted to a rectangular coordinate value. Therefore, highly accurate shape measurement can be reliably performed.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 are views showing a preferred embodiment of a shape measuring apparatus according to the present invention.
FIG. 3 is a diagram showing the overall configuration. 7 and 9
Parts having the same structure as the conventional shape measuring apparatus shown in FIG. Further, in the same figure, a personal computer, a controller driver and the like are omitted.

In FIG. 1, 1 is an optical displacement meter, 10
Is an XY stage including an X stage 11 and a Y stage 12, and constitutes a movable table. The displacement meter 1 is installed on the upper surface of the Y stage 12 such that its detection direction is parallel to the moving direction of the Y stage 12, that is, the Y axis direction. Further, the DUT 2 is set on the set table 3 outside the XY stage 10.

The displacement meter 1 connects a minute spot to the surface of the object 2 to be measured, converts the reflected light into an electric signal and outputs it as a detection signal, and detects a measurement point P on the surface of the object 2 to be measured. Is. The measuring range of the displacement meter 1 is, for example, ± 0.5 μ
When the minute spot is within this range, a detection signal proportional to the displacement is output. An optical displacement meter that is not in contact with the object to be measured 2 is advantageous in that it has extremely high sensitivity, and is small and lightweight. However, the invention is not limited to this. For example, a stylus type or an eddy current is used. You can also use it.

The Y stage 12 is provided integrally with the main body of the Y stage 12 and includes a plate member 12a protruding from the main body of the Y stage 12, and the upper surface of the main body of the Y stage 12 and the upper surface of the plate member 12a are flush with each other. Is formed. On the upper surface of the plate member 12a, in order to measure the amount of movement of the X stage 11 in the X axis direction, a laser interferometer 2 for measuring the X coordinate is used.
3, the emitting portion 33a of the optical fiber cable 33 and the receiver 25 are set. Further, on the upper surface of the main body of the Y stage 12, in order to measure the movement amount of the Y stage 12 in the Y-axis direction, the laser interferometer 24 for measuring the Y coordinate, the emitting portion 34 a of the optical fiber cable 34, and the receiver 26.
Is set.

Outside the XY stage 10, a reference plane mirror 31 for X coordinate measurement, a reference plane mirror 32 for Y coordinate measurement, a laser light source 21 and a prism 22 are provided. The reference plane mirror 31 for X-coordinate measurement is set on a set stand (not shown) so that its reflection surface 31a is orthogonal to the X-axis direction of the XY stage 10, and a laser emitted from a laser interferometer 23 described later. It reflects light and forms a length-measuring optical path with the laser interferometer.

The reference plane mirror 32 for measuring the Y coordinate is set on the set table 4 so that its reflection surface 32a is orthogonal to the Y axis direction of the XY stage 10, and is emitted from the laser interferometer 24 described later. The laser beam is reflected to form a length measurement optical path with the laser interferometer 24.
The laser light source 21 generates a frequency-stabilized laser light. As the laser light, for example, a gas laser such as a He-Ne laser is used. The laser light emitted from the laser light source 21 is split into two by the prism 22, one laser light is guided to the laser interferometer 23 through the optical fiber cable 33, and the other laser light is interfered by the laser through the optical fiber cable 34. The light is guided to a total of 24. That is, the laser light source 21, the prism, and the optical fiber cables 33 and 34 form a laser supply system.

The laser interferometer 23 for measuring the X coordinate is shown in FIG.
As shown in, the beam splitter 23a, the corner cube prism 23b, and the plane mirror 23c are included. The beam splitter 23a splits the laser light incident through the optical fiber cable 33 into a measuring light and a reference light, and as shown in FIG. Prism 2
2B while forming a length measurement optical path through 3b.
As shown in, the reference optical path is formed between the plane mirror 23c and the corner cube prism 23b.

The length-measuring light makes two round trips to and from the reference plane mirror 31 as shown by the arrow in FIG. 2A, and the reference light is a plane as shown by the arrow in FIG. 2B. Mirror 23c
2 round trips between and are received by the receiver 25,
The bright / dark signal (interference signal) is counted by a length measuring counter (not shown). The length measurement counter counts the number of repetitions of the light / dark signal detected by the receiver according to the change in the distance L between the reference plane mirror 31 and the laser interferometer 23. For example, when the distance L changes by the wavelength λ of the laser light, the optical path difference between the measurement light and the reference light becomes 4λ, and the receiver 25 detects the bright and dark signals four times.
The number of times of detection is counted by the length measuring counter. In practice, this light / dark signal is further divided by an electrical method to improve the resolution of the laser interferometer. As the resolution, λ / 128 and λ = 633 nm are general.

The laser interferometer 23 for measuring the X coordinate, the emitting portion 33a of the optical fiber cable 33, and the receiver 25.
Is indicated by an imaginary line A in FIG. 2A, and the central axes of the two measuring optical paths formed between the beam splitter 23a and the reference plane mirror 31 indicate the measuring point P of the displacement meter 1. Street, X
It is arranged on the upper surface of the plate-shaped member 12a of the Y stage 12 so as to be parallel to the X-axis direction of the Y stage 10.

A laser interferometer 24 for measuring the Y coordinate is also provided.
Is also configured similarly to the laser interferometer 23, and the laser interferometer 24 for Y coordinate measurement, the emitting portion 34a of the optical fiber cable 34, and the receiver 25 are formed between the beam splitter 24a and the reference plane mirror 32. The central axes of the two measured optical paths are passed through the measurement point P of the displacement gauge 1 and XY
It is arranged on the upper surface of the Y stage 12 so as to be parallel to the Y-axis direction of the stage 10.

In the shape measuring apparatus of the present embodiment, the central axis of the measuring optical path formed between the laser interferometer 23 for measuring the X coordinate and the reference plane mirror 31 is the measuring point P of the displacement meter 1.
The laser interferometer 23, the emitting portion 33a of the optical fiber cable 33, and the receiver 25 are arranged on the upper surface of the plate-shaped member 12a of the Y stage 12 so as to be parallel to the X axis direction of the XY stage 10. , The central axis of the length measuring optical path formed between the laser interferometer 25 for measuring the Y coordinate and the reference plane mirror passes through the measuring point P of the displacement meter 1 and XY
The laser interferometer 24, the emitting portion 34a of the optical fiber cable 34, and the receiver 26 are arranged so as to be parallel to the Y-axis direction of the stage 10 (axial direction parallel to the detection direction of the displacement meter 1).
Are arranged on the upper surface of the Y stage 12.

Therefore, the influence of the straightness error due to the movement of the XY stage 10 can be eliminated, and the movement amount in each axial direction of the moving table can be measured while eliminating the Abbe error. The shape of an object can be measured with high accuracy. Further, since it is not necessary to make the members such as the guide of the XY stage 10 highly accurate, the cost of the measuring device can be reduced.

Further, since the laser light emitted from the laser light source 21 and divided into two by the prism 22 can be guided to the laser interferometers 23 and 24 through the optical fiber cables 33 and 34, the laser light source 21 is moved to the XY stage. It can be installed at a free position apart from above 10. Therefore, the degree of freedom in the layout of the laser supply system can be improved, and the device can be made compact.

In general, the laser light source 21 is not suitable for mounting on the XY stage 10 because of its size and weight, but in the shape measuring apparatus of this embodiment, the displacement meter 1 and the laser interferometer are used. 23, 24, receiver 25, 2
6, and the emission parts 33a, 3 of the optical fibers 33, 34
4a is arranged on the XY stage 10. They are,
Since the weight is light and constant, the XY stage 10
It is easy to design the actuators 13 and 14 that reduce the moving load of the actuators and realize a suitable followability. Especially DUT 2
It is effective when the weight of the reference plane mirrors 31 and 32 is larger than these weights.

(Second Embodiment) FIG. 3 is a diagram showing a configuration of a shape measuring apparatus according to a second embodiment of the present invention. In addition, the same reference numerals are given to the same components as those of the shape measuring apparatus shown in FIGS. 1 and 9 for description. Also in this figure, a personal computer, a controller driver, etc. are omitted.

As shown in FIG. 3, in the shape measuring apparatus of this embodiment, contrary to the shape measuring apparatus shown in FIG. 1, the object to be measured 2 and the reference plane mirror 20 are arranged on the Y stage 11. The displacement gauge 1, the laser interferometers 23 and 24, and the receivers 25 and 26 are arranged outside the XY stage 10. Reference numeral 20 is a reference mirror for measuring the X coordinate and the Y coordinate, and the mirror surface 20a and the mirror surface 20b are formed so as to form a right angle with each other with high accuracy, and are orthogonal to the X axis direction and the Y axis direction of the XY stage 10, respectively. Like X
It is set on the Y stage 10.

The laser interferometer 23a and the receiver 25 for measuring the X coordinate are composed of the laser interferometer 23 and the reference plane mirror 2.
The center axis of the length-measuring optical path formed between the reflection surface 20a of 0 and the reflection surface 20a passes through the measurement point P of the displacement meter 1,
It is arranged so as to be parallel to the axial direction. Similarly, in the laser interferometer 23 a for measuring the Y coordinate and the receiver 25, the central axis of the length-measuring optical path formed between the laser interferometer 24 and the reflecting surface 20 b of the reference plane mirror 20 is similar to that of the displacement meter 1. It is arranged so as to pass through the measurement point P and be parallel to the Y-axis direction of the XY stage 10.

Therefore, even in this shape measuring apparatus,
It is possible to eliminate the influence of the straightness error due to the movement of the XY stage 10 and measure the axial movement amount of each of the moving bases while eliminating the Abbe error. Therefore, the shape of the object to be measured can be measured with high accuracy. Further, since it is not necessary to make the members such as the guide of the XY stage 10 highly accurate, the cost of the measuring device can be reduced.

Further, since the displacement meter 1, the receivers 25 and 26, the optical fiber cables 31 and 32 shown in FIG. 1 and the like are provided outside the XY stage 10, these wirings are used when the XY stage 10 moves. The device configuration is simplified without any hindrance. In the present embodiment, the laser light emitted from the laser light source 21 is split by the prism 22 and directly guided to the laser interferometers 23 and 24.
Needless to say, when the light guide is performed using the optical fiber cable as in the shape measuring device shown in FIG. 1, the laser light source 21 can be installed at a free position, and the device can be downsized. .

In the first embodiment, the displacement meter 1, the laser interferometers 23, 24, etc. are arranged on the XY stage 10, and the DUT 2 and the reference plane mirrors 31, 32 are XY. It is arranged outside the stage, and in the second embodiment, the DUT 2 and the reference plane mirror 20 are arranged on the XY stage 10, and the displacement meter 1 and the laser interferometer 2 are arranged.
Although 3, 24 and the like are arranged outside the XY stage, the displacement gauge and the reference plane mirror are arranged on the XY stage 10,
The object to be measured, the laser interferometer, etc. may be arranged outside the XY stage 10, or the object to be measured, the laser interferometer, etc. may be arranged on the XY stage, and the displacement meter and the reference plane mirror are arranged in the XY stage. It may be arranged outside the stage. These are, for example, the size and weight of the object to be measured, the moving load of the XY stage,
The optimum combination may be selected from the viewpoint of ease of installation.

(Third Embodiment) FIG. 4 is a diagram showing the configuration of a shape measuring apparatus according to a third embodiment of the present invention. It should be noted that components having the same configurations as those of the shape measuring apparatus shown in FIG. 1 and FIG. Also in this figure, a personal computer, a controller driver, etc. are omitted.

In FIG. 4, the displacement meter 1 is set on a Y stage 40 provided on the Y stage 12 of the XY stage 10, and the DUT 2 is set outside the XY stage 10. The Y stage 40 is slightly moved in the Y-axis direction parallel to the detection direction of the displacement meter 1 by an actuator (not shown), and its moving stroke is ± 1 mm.

Reference numerals 41 and 42 denote frequency-stabilized semiconductor lasers, which form a laser supply system. The semiconductor laser has a shorter coherence length than the He-Ne laser,
It is difficult to obtain a stable wavelength, but it is easy to install because it is small and lightweight. The reference mirror 32 for measuring the Y coordinate is arranged outside the XY stage 10 so that its reflection surface is orthogonal to the Y axis direction of the XY stage 10. Further, in the laser interferometer 24, the semiconductor laser 42, and the receiver 26 for measuring the Y coordinate, the central axis of the measuring optical path formed between the laser interferometer 24 and the reference plane mirror 32 is the measurement point of the displacement meter 1. It is arranged on the Y stage 40 so as to pass through P and be parallel to the Y axis direction of the XY stage 10. The reflection surface of the reference mirror 32 for measuring the X coordinate is the XY stage 10.
Is arranged outside the XY stage 10 so as to be orthogonal to the X axis direction. Further, the laser interferometer 24 for measuring the X coordinate, the semiconductor laser 42, and the receiver 26, when the Y stage 40 is located at the origin of the center of the stroke,
The central axis of the measuring optical path formed between the laser interferometer 24 and the reference plane mirror 32 passes through the measurement point P of the displacement meter 1,
It is arranged on the plate-shaped member 12a of the Y stage 12 so as to be parallel to the Y-axis direction of the XY stage 10.

The Y stage 10 is moved at a low speed by the actuator 14 so that the measuring point P substantially follows the shape of the DUT 2 based on the fluctuation of the detection signal of the displacement gauge 1 in the low frequency band. ing. On the other hand, Y stage 4
In 0, the measurement point P is moved at high speed based on the high frequency signal of the detection signal of the displacement meter 1 so as to follow the vibration of the XY stage 10 and the surface roughness of the DUT 2. That is, the XY stage 10 corresponds to the first moving table, and the Y stage 40 corresponds to the second moving table.

The shape measuring apparatus of the present embodiment shares the control band of the Y stage 10 and the Y stage 40, and moves the Y stage 10 and the Y stage independently by their respective actuators, so that the low frequency band to the high frequency band can be increased. This is to speed up the measurement as compared with the case where the vibration up to the band is covered by the Y stage 10 alone.

Originally, the Y stage 40 is provided with the laser interferometer 24 for measuring the Y coordinate and the laser interferometer 23 for measuring the X coordinate so as to move not only in the Y axis but also in the X axis direction. Ideally, However, even if the moving direction of the Y stage 40 is only the Y-axis direction,
If 0 can be moved at a high speed, the Y stage 40 can be moved so that the measurement point P of the displacement meter 1 moves along with the DUT 2 while keeping it within the measurement range of the displacement meter 1. Therefore, the movement stroke of the Y stage 10 is reduced. The moving stroke varies depending on the conditions such as the moving load of the Y stage 40, but is within ± 2 mm, preferably within ± 1 mm.

When the laser interferometer 23 for measuring the X coordinate is arranged on the Y stage 40, the Y stage 4
As the size of 0 increases, the weight of the Y stage 40 including the displacement meter 1 and the laser interferometers 23 and 24 increases, and the moving load of the Y stage increases. Also, X
If it is attempted to move it in the axial direction as well, it is necessary to newly provide an X stage, which increases the weight of the stage and complicates the structure of the stage.

This is because the Y-axis direction is parallel to the detection direction of the displacement meter 1 and has the greatest effect on measurement accuracy. Whether the second moving table is an XY stage or a uniaxial stage, and which of the respective coordinates is to be equipped with a laser interferometer for coordinate measurement or the like is determined in consideration of the measurement accuracy and cost required for the measuring device. And decide. As described above, in the present embodiment, the moving stage includes the XY stage 10 that moves independently in the X-axis and Y-axis directions, and the Y stage 40 that is mounted on the XY stage 10 and moves independently in the Y-axis direction.
And the Y stage 12 is moved so as to follow the fluctuation of the detection signal of the displacement meter 1 in the low frequency band, and the Y stage 40 follows the fluctuation of the detection signal of the displacement meter 1 in the high frequency band. It is configured to move.

Therefore, the Y stage 12 is moved so that the fluctuation of the low frequency band, that is, the measurement point substantially follows the shape of the object to be measured, and the Y stage 40 is changed of the high frequency band, that is, the XY stage 10. It is possible to move the measurement point by moving so as to follow the vibration and the surface roughness of the DUT 2 and sharing the control band. Therefore, the measurement can be speeded up.

Further, the semiconductor laser 4 is small and lightweight.
Since the laser supply system is composed of 1, 42, the size of the entire apparatus can be significantly reduced. Further, for example, the laser supply system can be arranged on the XY stage 10 and the Y stage 40, and the degree of freedom in the layout of the laser supply system can be improved. Although a semiconductor laser is used as the laser supply system in the present embodiment, the laser light emitted from the laser light source 21 is passed through the optical fiber cables 33 and 34 as in the shape measuring apparatus shown in FIG. It goes without saying that the laser interferometers 23 and 24 may be supplied.

Further, in the above-mentioned first to third embodiments,
For ease of explanation, the two-dimensional shape measuring apparatus in which the measurement point P moves on the XY plane composed of the X axis and the Y axis orthogonal to each other has been described.
Of course, the present invention can be applied to a three-dimensional shape measuring device that moves in the directions of the axis, the Y axis, and the Z axis. In addition, in the first to third embodiments described above, both the X coordinate and the Y coordinate are measured using the laser interferometer, but only for the coordinate in the axial direction parallel to the detection direction of the displacement meter. A laser interferometer may be used. The measurement accuracy in the axial direction parallel to the detection direction of the displacement gauge is the factor that most affects the measurement accuracy of the object to be measured.If this measurement accuracy in the axial direction is high, the measurement accuracy in the other axial directions will be slightly reduced. This is also because high measurement accuracy of the measured object can be obtained. That is, whether the laser interferometer is used for both the X coordinate and the Y coordinate or for the Y coordinate (coordinate in the axial direction parallel to the displacement meter) depends on the required accuracy of the shape measuring device. Just decide.

By the way, using the laser interferometer, XY
When measuring the amount of movement of the stage or the XYZ stage in each axial direction, each axial direction is the normal direction of the reflecting surface of each reference plane mirror. In practice, it may be difficult to arrange the reference plane mirrors at right angles to each other, and strictly speaking, the shape measurement is performed in a non-orthogonal coordinate system. Therefore, if the squareness of each reference mirror is measured in advance and a means for converting the measured value in each axial direction measured by the laser interferometer to ideal Cartesian coordinates is provided in, for example, a personal computer, More accurate shape measurement can be performed.

FIG. 5 shows an actual coordinate system X'Y'Z 'formed by a plurality of reference plane mirrors and an ideal orthogonal coordinate system X.
It is a figure which shows the relationship with YZ. Actual coordinate system X'Y'Z
If the coordinates of an arbitrary point u in ′ are represented by (x ′, y ′, z ′), and the coordinates of the point u in the ideal Cartesian coordinate system XYZ are represented by (x, y, z), The following relation holds for.

[0066]

[Equation 1]

Where ix, jx, kx are unit vectors in the X direction, iy, jy, ky are unit vectors in the Y direction, and iz, jz, kz are unit vectors in the Z direction. Is determined in advance by measuring the squareness of each reference plane mirror. By calculating the inverse matrix of the matrix shown in Expression (1) based on these coefficients,
As shown in the following equation, the coordinates of the point u are (x ', y', z ')
Can be converted into the coordinates of the point u into (x, y, z).

[0068]

[Equation 2]

Specifically, as shown in FIG. 8, for example, the X'Y 'axis of the actual coordinate system X'Y'Z' and the plane are the same plane as the XY plane of the ideal coordinate system XYZ. Share and Y '
When the axes are set so as to coincide with each other, the angle α formed by the Y-axis direction component of the Z′-axis and the Z-axis, the angle β formed by the X-axis direction component of the Z′-axis and the Z-axis, and X The angle γ formed by the ‘axis and the X axis can be measured. At this time, equation (1)
The matrix and the inverse matrix shown in are respectively as follows.

[0070]

(Equation 3)

[0071]

(Equation 4)

Using this inverse matrix, the coordinate values actually measured by the laser interferometer are converted into the coordinate values in the ideal rectangular coordinate system.

[0073]

According to the invention described in claim 1, each measurement formed between the laser interferometer and the reference mirror of the laser interferometer, which corresponds to at least the axial direction parallel to the detection direction of the displacement meter. The reference mirror and the laser interferometer are arranged so that the central axis of the long optical path passes through the measurement point of the object to be measured and is aligned with a straight line parallel to the axial direction of the movable table. For this reason,
The laser interferometer can measure the displacement of the displacement table moving table in the axial direction corresponding to at least the detection direction of the displacement meter while eliminating the Abbe error, so the shape of the measured object can be measured with high accuracy. can do. Further, since it is not necessary to make the members such as the XY stage or the XYZ stage and the guide highly accurate, the cost of the measuring device can be reduced.

According to the second aspect of the present invention, a plurality of the laser interference measuring devices are provided so as to measure the amount of movement of each of the movable bases in the respective axial directions. The reference mirrors and the laser interferometers are arranged so that the central axes of the long optical paths pass through the measurement points of the object to be measured and are aligned on a straight line parallel to the axial direction of the movable table. Therefore, it is possible to measure the amount of movement of the displacement table in the axial direction corresponding to at least the detection direction of the displacement meter while eliminating the Abbe error by the laser interferometer measuring device corresponding to all the axial directions of the displacement table. Therefore, it is possible to reliably perform highly accurate shape measurement.

According to the third aspect of the present invention, since the laser light emitted from the laser light source is guided by the optical fiber to the laser interferometers corresponding to the respective axial directions of the moving table, the laser light source generator and the like can be provided. It can be installed at a free position apart from the moving table or its surroundings. Also,
The emitting part of the optical fiber can be installed on the movable table. Therefore, the degree of freedom in the layout of the laser supply system can be improved, and the device can be made compact.

According to the invention described in claim 4, since the laser supply system comprises a semiconductor laser, as compared with the case of using a gas laser represented by a helium-neon laser,
The entire device can be significantly downsized. In addition, since the semiconductor laser can be installed on the movable table, the degree of freedom in the layout of the laser supply system can be improved.

According to the invention of claim 5, the object to be measured and the reference mirror are fixed to the movable table, and the displacement gauge, the laser interferometer and the laser supply system are fixed to the outside of the movable table. To be done. For this reason, for example, the output of the receiver and the wiring for obtaining can be arranged outside the moving table, so that the wiring does not obstruct the movement of the moving table and the device configuration is simplified.

According to a sixth aspect of the present invention, the displacement gauge, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the movable table, and the object to be measured and the reference mirror are fixed. Is fixed to the outside of the moving table. Therefore, the displacement meter, the laser interferometer, and the emission part of the optical fiber or the semiconductor laser have a light weight and a constant weight, so that the moving load of the movable table is reduced and the actuator is designed to realize a suitable followability. Will be easier. This is particularly effective when the weight of the object to be measured is larger than the weights of the displacement meter and the laser interferometer.

According to the invention as set forth in claim 7, the movable table is provided with a first movable table which moves independently in each of the axial directions, and is mounted on the first movable table, the displacement gauge and the object to be measured. And a second moving table which fixes either one of them and independently moves in at least an axial direction parallel to the detection direction of the displacement meter in each of the axial directions.
With respect to the axial direction in which the movable table can move, the first movable table is moved so as to follow the fluctuation in the low frequency band of the detection signal of the displacement gauge, and the second movable table is moved to the high frequency of the detection signal of the displacement gauge. It is configured to move so as to follow the fluctuation of the band. For this reason, the moving means moves the first moving table in a low frequency band, that is, the measurement point moves so as to substantially follow the shape of the object to be measured, and the second moving table moves in a high frequency band, that is, the first moving table. It is possible to move the measuring point by moving the moving table so as to follow the vibration of the moving table and the surface roughness of the object to be measured and sharing the control band. Therefore, the measurement can be speeded up.

According to the eighth aspect of the invention, since the laser light emitted from the laser light source is guided by the optical fiber to the laser interferometers corresponding to the respective axial directions of the movable table, the laser light source generator and the like can be provided. It can be installed at a free position apart from the moving table or its surroundings. Also,
The emitting part of the optical fiber can be installed on the movable table. Therefore, the degree of freedom in the layout of the laser supply system can be improved, and the device can be made compact.

According to the ninth aspect of the present invention, the laser supply system is composed of a plurality of semiconductor lasers.
Compared to the case of using a gas laser typified by e-laser,
The entire device can be significantly downsized. Further, since the semiconductor laser can be installed on the moving table, the degree of freedom in the layout of the laser supply system can be improved.

According to the invention of claim 10, the object to be measured and the reference mirror are fixed to the second movable table,
The displacement meter, the laser interferometer, and the laser supply system are fixed to the outside of the movable table. Therefore, for example, the output of the receiver and the wiring for obtaining can be arranged outside the moving table, so that the wiring does not become an obstacle when the moving table is moved, and the device configuration is simplified.

According to the eleventh aspect of the present invention, the displacement meter, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the second moving table,
The object to be measured and the reference mirror are fixed to the outside of the movable table. For this reason, the displacement meter, the laser interferometer, and the emitting part of the optical fiber or the semiconductor laser have a light weight and a constant weight, so that the moving load of the first and second moving bases is reduced and the moving base is suitable. This makes it easy to design an actuator that achieves tracking. This is particularly effective when the weight of the object to be measured is larger than the weights of the displacement meter and the laser interferometer.

According to the twelfth aspect of the present invention, the displacement gauge, the laser interferometer corresponding to the movable axial direction of the second movable table, and the emitting section of the optical fiber or the semiconductor laser are arranged in the first and second sections. The laser interferometer and the emitting portion of the optical fiber or the semiconductor laser corresponding to an axial direction other than the movable axial direction of the second movable table are fixed to the second movable table, and are fixed to the first movable table. The object to be measured and the reference mirror are fixed to the outside of the movable table.
Ideally, all the laser interferometers corresponding to each axial direction should be fixed to the second moving table, but the moving load of the second moving table becomes large, and suitable followability of the second moving table is obtained. It may not be possible. Therefore, by reducing the number of laser interferometers fixed to the second moving table and reducing the moving load of the second moving table, the movement of the second moving table can be accelerated. At this time, even if the remaining laser light source and the laser interferometer are on the first movable table, sufficient followability can be obtained without causing an Abbe error.

According to the thirteenth aspect of the present invention, the perpendicularity between the plane mirrors corresponding to the respective axial directions is obtained in advance, and the perpendicularity of each axial direction measured by the laser interferometer by the conversion means is measured. Convert the measured values into ideal rectangular coordinate values. Therefore, highly accurate shape measurement can be reliably performed.

[Brief description of drawings]

1 shows a shape measuring apparatus according to a first embodiment of the present invention, in which FIG. 1 (a) is a plan view of relevant parts, FIG.
(B) is a front view of the main part.

FIG. 2 is an enlarged view showing a main part of the laser interferometer 23 shown in FIG. 1, FIG. 2 (a) showing a length measuring optical path thereof, and FIG. 2 (b) showing a reference optical path thereof. Is.

FIG. 3 shows a shape measuring apparatus according to a second embodiment of the present invention, FIG. 3 (a) is a plan view of relevant parts,
(B) is a front view of the main part.

FIG. 4 is a diagram showing a shape measuring apparatus according to a third embodiment of the present invention, FIG.
(B) is a front view of the main part.

FIG. 5 is a diagram showing a relationship between a non-orthogonal coordinate system X′Y′Z ′ actually measured by the shape measuring apparatus according to the present invention and an ideal rectangular coordinate XYZ system.

FIG. 6 is a diagram showing a method for measuring an error between a non-orthogonal coordinate system X′Y′Z ′ actually measured by the shape measuring apparatus according to the present invention and an ideal orthogonal coordinate XYZ system.

7 is a diagram showing an example of a conventional shape measuring apparatus, and FIG.
FIG. 5A is a plan view of relevant parts, and FIG. 5B is a front view of relevant parts.

8 is a diagram showing a measuring operation of the shape measuring apparatus shown in FIG.

9A and 9B are views showing an example of a conventional shape measuring apparatus, FIG. 7A is a plan view of a main part thereof, and FIG. 7B is a front view of the main part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Displacement meter 2 Object to be measured 3, 4, 5, 6 Set stage 10 XY stage (moving stage, first moving stage) 11 X stage 12 Y stage 13, 14 Actuator (moving means) 15, 16 Controller driver 17, 18 Linear encoder 19 Personal computer (converting means) 20, 31, 32 Reference plane mirror (reference mirror) 20a, 31a, 32a Reflecting surface 21 Laser light source (laser supply system) 22 Prism (laser supply system) 23, 24 Laser interferometer 23a , 24a Beam splitter 23b, 24b Corner cube prism 23c, 24c Planar mirror 25, 26 Receiver 33, 34 Optical fiber cable (laser supply system) 33a, 34a Optical fiber cable injection part 40 Y stage (2nd moving stand) 41, 42 Semiconductor laser The supply system)

Claims (13)

[Claims] 1. A displacement meter for detecting a measurement point on the surface of an object to be measured, and either one of the displacement meter and the object to be measured is fixed, and each of them includes an axis parallel to the detection direction of the displacement meter. X almost orthogonal
A moving table that moves independently in at least two axial directions among the axes, Y-axis, and Z-axis, and a measurement point that moves the measurement point along the surface of the measured object while the displacement sensor keeps the detection signal of the measurement point substantially constant. To move the movable table independently in each axial direction so as to correspond to at least the axial direction parallel to the detection direction of the displacement gauge in each axial direction of the movable table, At least a reference mirror including a reflection surface that becomes a laser, a laser interferometer that forms a length measurement optical path between the reference mirror and a reflection surface of the reference mirror, and a laser supply system that supplies laser light to the laser interferometer. A laser interferometer, and a shape measuring device for measuring a surface shape of an object to be measured based on a length measurement result of the laser interferometer. The central axis is the object to be measured. Through the measurement point, to match the moving base in the axial direction and parallel to a straight line, the shape measuring apparatus being characterized in that disposed a reference mirror and laser interferometer. 2. A plurality of the laser interferometers are provided so as to measure the amount of movement of the movable table in each axial direction, and the central axes of the length measuring optical paths of the plurality of laser interferometers are respectively arranged. The shape measuring device according to claim 1, wherein each of the reference mirrors and the laser interferometers are arranged so as to coincide with a straight line that passes through a measurement point of the object to be measured and is parallel to an axial direction of the movable table. apparatus. 3. The shape measuring apparatus according to claim 1, wherein the laser supply system has an optical fiber that guides laser light emitted from a laser light source to the laser interferometer. 4. The shape measuring apparatus according to claim 1, wherein the laser supply system comprises a semiconductor laser. 5. The object to be measured and the reference mirror are fixed to the movable table, and the displacement meter, the laser interferometer and the laser supply system are fixed to the outside of the movable table. Item 5. The shape measuring device according to any one of items 1 to 4. 6. The displacement meter, the laser interferometer, and
5. The shape measuring apparatus according to claim 3, wherein the emitting part of the optical fiber or the semiconductor laser is fixed to the movable table, and the object to be measured and the reference mirror are fixed to the outside of the movable table. . 7. A first moving table, wherein the moving table is independently movable in each of the axial directions, and is mounted on the first moving table, and fixes either one of the displacement gauge and the object to be measured. And a second moving table that independently moves in at least one of the axial directions parallel to the detection direction of the displacement gauge, wherein the moving means is an axial direction in which the second moving table can move. On the other hand, the first moving table is moved so as to follow the fluctuation in the low frequency band of the detection signal of the displacement meter, and the second moving table is moved so as to follow the fluctuation in the high frequency band of the detection signal of the displacement meter. The shape measuring apparatus according to claim 1 or 2, wherein the shape measuring apparatus is moved. 8. The shape measuring apparatus according to claim 7, wherein the laser supply system has an optical fiber that guides laser light emitted from a laser light source to the laser interferometer. 9. The shape measuring apparatus according to claim 7, wherein the laser supply system is a semiconductor laser. 10. The object to be measured and the reference mirror are fixed to the second moving table, and the displacement meter, the laser interferometer and the laser supply system are fixed to the outside of the moving table. The shape measuring device according to any one of claims 7 to 9. 11. The displacement meter, the laser interferometer, and the emitting section of the optical fiber or the semiconductor laser are fixed on the second movable table, and the object to be measured and the reference mirror are external to the movable table. The shape measuring device according to claim 8 or 9, wherein the shape measuring device is fixed to the. 12. The displacement gauge, and the laser interferometer corresponding to an axial direction parallel to the detection direction of the displacement gauge of the second moving table and the emitting part of the optical fiber or the semiconductor laser, the second gauge. The laser interferometer and the emission part of the optical fiber or the semiconductor laser, which is fixed to a moving table and corresponds to an axial direction other than the axial direction corresponding to the axial direction parallel to the detection direction of the displacement meter, is the first moving table. 10. The shape measuring apparatus according to claim 8, wherein the object to be measured and the reference mirror are fixed to the outside of the movable table. 13. Ideally orthogonal measured values in each axial direction measured by a laser interferometer based on an error in squareness between reference mirrors corresponding to each axial direction which is obtained in advance. The shape measuring device according to any one of claims 1 to 12, further comprising a converting unit that converts the coordinates into coordinate values.